This invention relates to a method for locating a mobile station in a mobile communication system; and more particularly, to a method for locating a mobile station based on a message supported by IS-95B standard in a CDMA mobile communication system or a PCS mobile communication system.
A representative one of conventional methods for locating a mobile station (MS) in a mobile communication system is to locate the MS based on a location registration message. The location registration message includes cell information, sector information or the like.
However, in case of locating the MS using the location registration message, there are a couple of following problems. It is possible to locate the MS approximately based on the cell information or the sector information but difficult to locate the MS exactly due to a difference between a computed distance and a measured distance to the MS. Also, it is not possible to locate the MS in real-time because the MS transmits the location registration message on a couple of predetermined conditions. For example, the MS transmits the location registration message by periods, at power-on, at power-off or the like.
It is an object of the present invention to provide a method for locating a mobile station (MS) based on a power-related message of base transceiver stations (BTS) in a mobile communication system to thereby locate the mobile station more exactly.
In accordance with an aspect of the present invention, there is provided a method for locating a mobile station (MS) based on a power-related message of base transceiver stations (BTS) in a mobile communication system, including the steps of: by a call control processor (CCP) of a base station controller (BSC), checking an active set that the mobile station currently holds; by the call control processor, determining if the active set is covered over three base transceiver stations; if the active set is not covered over the three base transceiver stations, by frequency allocation of the active set, reading out status information of neighboring base transceiver stations; by the call control processor, determining if the frequency allocation of the active set is usable; if the frequency allocation is usable, transmitting to the mobile station a PSMRO (pilot strength message request order) message for requesting to measure pilot strength of the frequency allocation; arranging a plurality of base transceiver stations in order of pilot strength based on the pilot strength measurement result and selecting 3 base transceiver stations having higher pilot strength; and directing the selected 3 base transceiver stations to be prepared to receive a PUF (power up function) pulse.